DE102022121927A1 - Measuring system for recording pressure measurements in a blood vessel - Google Patents

Abstract

The invention relates to a measuring system for recording pressure measurements in a patient's blood vessel. The measuring system comprises a multi-arm connection (10), which includes a first connection arm (12), a second connection arm (14) and a third connection arm (16), which are in fluid communication with one another. The first connection arm (12) can be fluidly connected to a pump device (40) in order to pass a fluid through. The second connection arm (14) can be connected to a patient-side cannula (30). Through the third connection arm (16), a measuring catheter (20) can be inserted into the patient-side cannula in a fluid-tight and displaceable manner. The measuring catheter (20) is designed to measure pressure values at a patient-side end (22) of the measuring catheter (20). The measuring system enables pressure measurements to be recorded at different positions within a blood vessel during operation of a pump device (40). The invention also relates to an extracorporeal membrane oxygenation arrangement with such a measuring system and a method for recording pressure measurements within a blood vessel (G) of a patient (P) using such a measuring system.

Description

TECHNICAL FIELD OF THE INVENTION

The present invention is in the field of recording pressure measured values within a blood vessel, in particular in the context of extracorporeal membrane oxygenation, and relates to a measuring system for recording pressure measured values in a blood vessel, which can in particular be a measuring system for an extracorporeal membrane oxygenation arrangement, which in combination can be used with such an arrangement with which a patient can receive extracorporeal membrane oxygenation therapy.

BACKGROUND

Pressure measurements are recorded within a blood vessel during numerous diagnostic and therapeutic measures. This can be done using a catheter that is inserted into the blood vessel being examined. An example of such measures is extracorporeal membrane oxygenation (“ECMO”).

Over the last few years, extracorporeal membrane oxygenation has developed into a relevant therapeutic option for the treatment of lungs and/or cardiopulmonary failure (cf. Peek GJ, Mugford M, Tiruvoipati R et al. CESAR trial collaboration. Efficacy and economic assessment of conventional ventilatory support versus extracorporeal membrane oxygenation for severe adult respiratory failure (CESAR): a multicenter randomized controlled trial. Lancet, 20095374(9698):1351-63.).

The establishment of ECMO therapy is of great and increasing importance, especially in the field of cardiac surgery and intensive care medicine. The possibility of enriching blood outside the human body with oxygen and freeing it of carbon dioxide, as well as supporting or replacing heart function, has revolutionized the treatment of highly complex clinical pictures and, in some cases, made it possible in the first place.

During ECMO therapy, at least two cannulas are usually inserted into a patient's bloodstream. Here, blood is sucked out of the patient's venous bloodstream through one of the cannulas and reintroduced elsewhere in the venous or arterial system through another cannula. A pump, for example a centrifugal pump, pumps the blood outside the body through an oxygenator, in which oxygen is enriched and carbon dioxide is eliminated. Depending on the cannula position, the function of the lungs - in the so-called veno-venous ECMO therapy (vv-ECMO therapy) - or both the lung function and the heart function - in the so-called veno-arterial ECMO therapy (va-ECMO therapy) - supports or replaces. In vv-ECMO therapy, the cannulas are inserted into veins of the organism. This supports the patient's lungs in their function or completely replaces the lung function. With va-ECMO therapy, the cannulas are inserted into at least one vein and one artery of the patient. As part of this therapy, not only lung function but also heart function is supported or replaced.

However, unwanted side effects can occur, particularly with va-ECMO therapy. The patient's blood is removed from the organism through a venous (draining) cannula and returned via an arterial (returning) cannula. The arterial cannula can be inserted, for example, via the femoral artery, as this is usually the most practical and quick-to-reach cannulation site. Here, the oxygen-enriched blood through an ECMO arrangement is pumped to the heart via the body's artery (aorta). As a result, on the one hand, blood is pumped through the heart into the aorta away from the heart (in the antegrade direction) and, on the other hand, at the same time, blood is pumped through the ECMO arrangement into the aorta towards the heart (in the retrograde direction), i.e. in the opposite direction. Thus, two opposing blood flows meet in the aorta and form a so-called watershed (cf. Hoeper MM, Tudorache I, Kühn C, Marsch G, Hartung D, Wiesner O, Boenisch O, Haverich A, Hinrichs J. Extracorporeal membrane oxygenation watershed. Circulation . 2014 Sep 2;130(10):864-5), usually in the area of the thoracic aorta, especially between the ascending aorta and the thoracic aorta.

In this sense, the heart and the ECMO arrangement work against each other. As the heart recovers during active ECMO therapy, the position of the point where the two blood streams meet (i.e. the position of the watershed) may change over time. The more the heart function recovers, the further the watershed migrates towards the arterial cannula (i.e. in the ECMO arrangement side direction or in the antegrade direction) due to the increasing pumping force of the heart, as long as the ECMO performance remains unchanged. Thus, the position of the watershed and its course can be used as an indicator to evaluate the convalescence of the heart.

In addition, the described interaction between the patient's native systemic circulation and the circulation driven by the ECMO arrangement has a significant influence on the distribution of oxygen-rich blood within the patient's vascular system. If the opposing blood flows meet below the left subclavian artery, the blood supply to the head remains dependent on the pumping power of the heart itself. However, if the lung function is inadequate, this can lead to a so-called watershed phenomenon or differential hypoxemia, which can lead to a reduced oxygen supply to organs and/or extremities in the upper half of the body (cf. Cove, ME Disrupting differential hypoxia in peripheral veno-arterial extracorporeal membrane oxygenation .Crit Care 19, 280 (2015).https://doi.org/10.1186/s13054-015-0997-3).

Although knowledge of the position of the watershed during ECMO therapy may be relevant for the reasons mentioned above, among others, there is currently no established technique for determining it during ongoing ECMO therapy. In this respect, there is scope for technical improvements in this area.

SUMMARY OF THE INVENTION

The present invention is based on the object of recording pressure measurements within a blood vessel. A particular object of the invention may be to enable the position of the watershed to be determined while ECMO therapy is ongoing and to overcome the above-mentioned disadvantages of the prior art in this regard. These tasks are solved by a measuring system according to claim 1 and by an ECMO arrangement according to claim 13. Preferred embodiments of the invention are set out in the dependent claims.

The invention relates to a measuring system for recording pressure measurements within a blood vessel. The measuring system can in particular be a measuring system for an extracorporeal membrane oxygenation arrangement, i.e. an ECMO arrangement. The measuring system can therefore be set up to be used in combination with an ECMO arrangement or in conjunction with it. However, the present invention may include other uses or suitability of the measurement system other than ECMO, in which pressure measurements are acquired within a blood vessel. An “ECMO arrangement” may generally be defined herein as a device configured to provide ECMO therapy to a patient. An ECMO arrangement can in particular include a pump device that can be connected to the measuring system according to the invention as explained below.

The measuring system according to the invention comprises a multi-armed connection and a measuring catheter. The multi-arm connection, which can in particular be a three-arm connection, comprises at least a first connection arm, a second connection arm and a third connection arm, whereby some embodiments may include one or more further connection arms. The first, second and third connection arms are in fluid communication with one another. This means that fluid flowing through the multi-arm port can flow through any of the port arms or into any of the other port arms as long as they are not blocked or closed to prevent this. The fluid referred to here can in particular be blood or a blood-containing fluid, but can also be another fluid, such as an infusion. The multi-armed connection can be designed, for example, as a three-armed Y-shaped connection.

The multi-arm connector may be made of a transparent material, for example a transparent plastic material. The multi-arm connection can be at least partially transparent.

The first connection arm of the multi-arm connection is designed to be fluidly connected to a pump device in order to pass a fluid through, in particular a fluid that is pumped in or pumped out by the pump device. The pump device can preferably be part of or include an ECMO arrangement. The fluid passed through the first connection arm can in particular be or include blood, which flows from the ECMO arrangement and/or into the ECMO arrangement during ongoing ECMO therapy. In this sense, the first connection arm can be connected to a corresponding port of the pump device, through which the pump device absorbs and/or delivers the fluid, e.g. blood. This port can, for example, be a port through which the said ECMO arrangement supplies or drains oxygen-enriched or oxygen-poor blood into the circulatory system of a patient through the multi-arm connection of the measuring system according to the invention. In this respect, the first connection arm is an arrangement-side connection arm of the multi-arm connection.

The second connection arm of the multi-arm connection is designed to be connected to a patient-side cannula in order to pass the fluid or blood passed through the first connection arm through the patient-side cannula lead. The patient-side cannula can in particular be an arterial cannula that is inserted into an artery of a patient, for example into the patient's inguinal artery. In this respect, the second connection arm is a patient-side connection arm of the multi-arm connection, through which the fluid, which can in particular be or include oxygen-enriched blood provided by the ECMO arrangement and received by the first connection arm, can be supplied to or removed from the circulatory system of a patient. The patient-side cannula can, for example, have a diameter of 5 mm (Charriere size 15) to 8,333 mm (Charriere size 25).

The first connection arm and the second connection arm can be designed in relation to the patient-side cannula in such a way that only the second connection arm can couple to the patient-side cannula or that the first connection arm is unsuitable for being coupled to the patient-side cannula. Alternatively or additionally, the first connection arm and the second connection arm can be designed in relation to the ECMO arrangement or its pump device in such a way that only the first connection arm can couple to the ECMO arrangement or that the second connection arm is unsuitable for this purpose ECMO arrangement to be coupled. In this way, a unique configuration of the multi-armed connection according to the invention can be determined in relation to the patient-side cannula and the ECMO arrangement, so that accidental reverse coupling of the multi-armed connection to the patient-side cannula is not possible.

The measuring catheter of the measuring system according to the invention can be inserted into the patient-side cannula through the third connection arm. The third connection arm is designed to accommodate the measuring catheter in a fluid-tight and displaceable manner and to feed it to the patient-side cannula through the second connection arm. “Fluid-tight” can mean in particular that the third connection arm is designed to accommodate the measuring catheter and at the same time prevent fluid from escaping from within the multi-arm connection through the third connection arm. For this purpose, the third connection arm can be provided with a suitable valve and/or valve mechanism. The valve or the valve mechanism can be or include a check valve. “Slidable” can mean in particular that the third connection arm is set up to accommodate the measuring catheter and at the same time enable the measuring catheter to be moved, for example in such a way that the length of a section of the measuring catheter that passes through the patient-side cannula or into a blood vessel of the Patient is recorded, can be adjusted, in particular freely adjustable, by appropriate adjustment of the penetration depth of the measuring catheter.

The measuring catheter and/or the third connecting arm can or can be provided with a fixing mechanism, which can be used to fix the position or the penetration depth of the measuring catheter. In this way, the position of the measuring catheter can be fixed when a desired penetration depth is reached in order to prevent accidental slipping. To change the penetration depth, the fixation mechanism can be actuated to free the measuring catheter and enable the measuring catheter to be moved again.

The measuring catheter of the measuring system according to the invention can be designed, in particular with regard to its length, to be displaceable through the multi-armed connection within a displacement range of at least 80 cm, preferably at least 100 cm, in order to achieve penetration positions along a patient's blood vessel in a corresponding range of at least to up to 80 cm, preferably at least up to 100 cm. These areas may particularly affect use in adults. When used in children, the areas can be adjusted or reduced accordingly, so that the measuring catheter of the measuring system according to the invention can be designed, in particular with regard to its length, to be displaceable through the multi-armed connection within a displacement range of at least 30 cm, preferably at least 50 cm to achieve penetration positions along a patient's blood vessel in a corresponding range of at least up to 30 cm, preferably at least up to 50 cm. “Penetration position” can refer to a distance from an entry point of the measuring catheter into the body or a blood vessel of a patient to the end of the measuring catheter on the patient side. If the patient-side end of the measuring catheter is at a penetration depth of, for example, 90 cm, this can correspond to a state in which a length of a section of the measuring catheter between the patient-side end of the measuring catheter and the mentioned entry point is 90 cm.

The measuring catheter of the measuring system according to the invention can have an elongated tubular configuration and can have an inner lumen through which a fluid connection can be established between the patient-side end of the measuring catheter and the patient-remote end of the measuring catheter, for example in order to take blood samples and/or to carry out an infusion add a patient's blood vessel. A diameter of the measuring catheter can correspond to a diameter of the patient-side cannula and/or the third and first connection arm can be adjusted. The measuring catheter can, for example, have a diameter of 3 mm (Charriere size 9) to 4 mm (Charriere size 12) and the inner lumen of the measuring catheter can, for example, have a diameter of 1 mm (Charriere size 3) to 2 mm (Charriere size 6).

The inner lumen of the measuring catheter can open at the patient-side end into a patient-side opening that is longitudinally aligned. With respect to a cross section of the measuring catheter in a plane perpendicular to the longitudinal direction of the measuring catheter, the patient-side opening can be arranged centrally. In comparison to other alignments and/or arrangements, this alignment and/or arrangement of the patient-side opening of the measuring catheter can enable a more precise and reliable detection of pressure measurements, in particular by a pressure sensor that is hydrostatically connected to the patient-side end of the measuring catheter and, for example, outside the body of the patient or at the end of the measuring catheter remote from the patient. This alignment and/or arrangement of the patient-side opening of the measuring catheter can further ensure that the patient-side opening does not rest directly on a side wall of the blood vessel being examined, which could impair the acquisition of the pressure measurement values or the fluid connection with the end remote from the patient.

The measuring catheter of the measuring system according to the invention is also set up to measure pressure measurements at a patient-side end of the measuring catheter. If the measuring catheter is guided through the multi-armed connection and through the patient-side cannula, so that the patient-side end of the measuring catheter is accommodated within a blood vessel, in particular within an artery of the patient, a pressure measurement value measured at the patient-side end of the measuring catheter corresponds to a fluid pressure or blood pressure within the The patient's blood vessel at the point where the patient-side end of the measuring catheter is located. It should be clear to the person skilled in the art that the patient-side end of the measuring catheter corresponds to the end of the measuring catheter that is inserted within the patient's blood vessel, while the opposite, patient-remote end of the measuring catheter can remain outside the patient's body and, for example, with a processor machine and / or can be connected to another machine.

A “pressure measurement value” may herein refer to a direct measurement of a fluid and/or blood pressure value or a pressure ratio within the blood vessel being examined, but may also refer to the detection of one or more physical parameters, such as a flow velocity, from which a pressure or a pressure ratio is determined within the examined blood vessel.

The measuring system according to the invention thus makes it possible to record pressure measurements at different positions within a patient's blood vessel while carrying out ECMO therapy, for example during operation or during pause times of a pump device that pumps a fluid into or from the blood vessel, in particular while carrying out ECMO therapy. The multi-arm connector is specifically designed to allow addition of the measurement catheter into a patient's blood vessel through which blood is pumped from the pumping device into the patient's circulatory system or vice versa, without affecting the extracorporeal flow conditions. Because the third connection arm can accommodate the measuring catheter in a fluid-tight and displaceable manner, the integrity and sterility of the process can be guaranteed, while the measuring catheter can be moved in relation to the multi-armed connection in order to adjust its penetration depth and thus different positions within the blood vessel To reach patients to record a pressure value there.

The measuring system according to the invention therefore allows pressure measurements to be recorded at various positions along a patient's blood vessel, in particular an artery, such as the inguinal artery, the iliac artery (pelvic artery), the abdominal aorta, and/or the thoracic aorta, while ECMO therapy is ongoing. during operation or pause times of a pumping device that may be part of an ECMO arrangement). As a result, the measuring system according to the invention can enable the position of the watershed, which corresponds to a local minimum of the pressure measured values, to be determined.

The measuring system according to the invention can, for example, be used to measure pressure values during ongoing or paused ECMO therapy at the patient-side end of the measuring catheter, while the patient-side end of the measuring catheter, coming from the patient-side cannula, gradually penetrates further into the patient's blood vessel system. As the penetration depth increases, the patient-side end of the measuring catheter can, for example, first pass through the inguinal artery, then the iliac artery (pelvic artery), then the abdominal aorta, and then the thoracic aorta. As the penetration depth of the catheter increases, the pressure readings initially gradually decrease the closer it is to the patient side The end of the measuring catheter comes to the watershed, as the counter pressure of the blood pumped from the heart towards the patient-side cannula increases with increasing proximity to the heart. From the point at which the end of the measuring catheter on the patient side reaches the position of the watershed, the measured pressure increases again as the catheter is inserted further, since the pressure of the blood stream pumped by the heart increases again after the impact point of both blood streams has been exceeded further towards the heart becomes. In this respect, the low point of a curve of the pressure measurements along the blood vessel corresponds to the exact position of the watershed.

The measuring system according to the invention thus enables the precise determination of the position of the watershed while ECMO therapy is ongoing. As a result of a reliable determination of the position of the watershed, complications that can occur with ECMO therapy, such as the aforementioned differential hypoxemia, can be recognized early and treated accordingly. Furthermore, an evaluation of the convalescence of the heart can be carried out by tracking the position of the watershed in real time.

According to a preferred embodiment of the invention, the measuring system can further comprise a processor unit which is communicatively connected to the measuring catheter and is set up to detect an penetration position of the measuring catheter, in particular the patient-side end of the measuring catheter. As a result, the penetration positions can be recorded reliably and partially or fully automatically by the processor unit when the measuring catheter is displaced. For this purpose, the processor unit can be equipped with a suitable position sensor system.

According to a preferred embodiment of the invention, the processor unit can further be set up to record pressure measurements measured by the measuring catheter and associated penetration positions of the measuring catheter. In other words, the processor unit can be set up to record value pairs “penetration depth or penetration position, measured pressure value” while the patient-side end of the measuring catheter moves through the patient's blood vessel, be it advancing or receding. By recording a plurality of such value pairs for different positions of the patient-side measuring catheter along the patient's blood vessel, the curve of the pressure measurement values along the blood vessel and thus the exact position of the watershed, which corresponds to a low point of the curve, can be determined reliably and automatically. The processor unit can also be set up to determine a penetration position that corresponds to a minimum pressure measurement value, in particular a local minimum or low point of the course of the pressure measurement values with varying penetration depth of the measurement catheter. This allows the processing unit to determine the position of the watershed.

In a preferred embodiment, the measuring catheter has length markings for determining an penetration position of the measuring catheter, in particular the patient-side end of the measuring catheter. The length markings can be or include, for example, optically detectable markings. The measuring catheter can be set up in such a way that the length markings are visible or detectable from outside the measuring catheter, in particular for a user or operator of the measuring catheter or for an optical detection device. For this purpose, a protective cover, in which the measuring catheter can be partially accommodated, and/or the multi-armed connection can be at least partially transparent. The length markings can be, for example, optical markings that are arranged on an outer surface of the measuring catheter. However, the length markings can alternatively or additionally be or include electronically and/or magnetically detectable markings which can be detected by a correspondingly set up detection sensor system. The length markings can in particular be arranged at regular intervals, so that the distance between two adjacent length markings, which can be, for example, 1 cm, 5 cm or 10 cm, is uniform. A user or operator of the measuring system according to the invention and/or a detection device can use the length markings to easily determine a penetration position of the measuring catheter, in particular the patient-side end of the measuring catheter, by observing the course of the length markings during each displacement of the measuring catheter. In other embodiments, the length markings may alternatively or additionally be or include haptic markings.

According to a preferred embodiment, the measuring catheter comprises a pressure sensor which is set up to measure the pressure measurements at the patient-side end of the measuring catheter. The pressure sensor can preferably be arranged at the patient-side end of the measuring catheter in order to directly measure a pressure there. This allows the pressure readings at the patient end of the measuring catheter to be measured with increased reliability and accuracy. In such embodiments, the pressure sensor arranged at the patient-side end of the measuring catheter can be equipped with an external control or processor unit, in particular with the one described above called processor unit, for example by means of a wire connection, which possibly extends through and within the measuring catheter, in order to transmit the pressure measurements measured by the pressure sensor to the external control or processor unit.

Alternatively or additionally, the measuring system according to the invention can comprise a pressure sensor which is hydrostatically connected to the patient-side end of the measuring catheter and is set up to measure the pressure measurements at the patient-side end of the measuring catheter. Such a pressure sensor can be arranged far away from the patient-side end of the measuring catheter, for example outside the patient's body and/or integrated in an external control or processor unit and/or in connection therewith. Due to the hydrostatic connection between the patient-side end of the measuring catheter and the pressure sensor, pressure measurement values that correspond to a pressure at the patient-side end of the measuring catheter can, although not directly at the patient-side end, be determined sufficiently reliably and precisely. By arranging the pressure sensor away from the patient-side end of the measuring catheter, for example at the end of the measuring catheter remote from the patient, the introduction of the measuring catheter into the patient's body can be less invasive and it is possible that wiring through the measuring catheter can be dispensed with.

For the purpose of the hydrostatic connection between the measuring catheter, in particular its patient-side end, and such a pressure sensor, the measuring catheter can be set up to be hydrostatically connected to the pressure sensor through a common Luer lock connection. This ensures compatibility of the measuring system according to the invention with pressure measuring systems or pressure sensors available on the market. The hydrostatic connection between the measuring catheter, in particular its patient-side end, and such a pressure sensor can take place through the inner lumen of the measuring catheter described above.

According to a preferred embodiment, the patient-side end of the measuring catheter can be blunt. As a result, the risk of injuries during the displacement of the measuring catheter along a patient's blood vessel and thus the invasiveness of the pressure measurements carried out with the measuring system according to the invention can be reduced. When the measuring catheter is inserted into the blood vessel of a patient, a blunt-shaped front tip of the measuring catheter, which can be round-shaped, for example, can prevent the blood vessel, in particular its inner wall, from being damaged by the front tip or the patient-side end of the catheter.

Alternatively or additionally, for this purpose, the patient-side end of the measuring catheter can be made of a softer material than other sections of the measuring catheter.

In preferred embodiments, the measuring catheter of the measuring system according to the invention can be accommodated in a protective cover, which can enclose a section of the measuring catheter outside the multi-arm connection and can preferably be designed to be attached to the third connection arm at a connection-side end. The protective cover can thus extend from a mouth or outer opening of the third connection arm and be attached thereto, so that the protective cover cannot unintentionally become detached from the third connection arm. The protective cover can be designed to guide a contact-free displacement of the measuring catheter. The protective cover can, for example, be designed as a tubular or accordion-shaped plastic cover. The protective cover can be at least partially transparent. The protective cover can have a length that can be equal to or greater than a length of the measuring catheter.

If a user or operator of the measuring system according to the invention wants to move the measuring catheter, for example deeper into a patient's blood vessel, he can operate the measuring catheter without direct contact through the protective cover. This means that the penetration depth of the measuring catheter can be adjusted using the protective cover under sterile conditions and without risk of contamination. A mechanism can be provided on the third connection arm of the multi-arm connection, for example a bayonet mechanism, to lock the protective cover. At the opposite end of the measuring catheter, that is to say at the end remote from the patient, the protective cover can also be attached, for example to the connection of the measuring catheter to a control unit, a processor unit and / or a pressure sensor (for example to the Luer lock connection mentioned above).

According to a preferred embodiment, the measuring system according to the invention can further comprise a closure element for closing the third connection arm, in particular an external opening of the third connection arm. The closure element can preferably close the third connection arm with a precise fit and/or in a fluid-tight manner. A mechanism can be provided on the third connection arm of the multi-arm connection, for example a bayonet mechanism, in order to releasably lock the closure element. This can be the same mechanism with which the protective cover described above can be attached, especially if the closure element has been removed. The closure element can be used to close the third connection arm, for example before insertion or after removal of the measurement catheter, in order to prevent accidental blood leakage and/or a risk of contamination.

The closure element may preferably have an inside section for plugging the third connection arm, wherein the inside section may have an end surface which is designed to lie flush with a side wall of the first and/or the second connection arm when the closure element closes the third connection arm . If the closure element therefore closes the third connection arm, the inside section can extend up to an interface between the third connection arm and the first and/or second connection arm, so that the closure element possibly completely seals and seals the third connection arm. In this state, the end surface of the inside section of the closure element can be aligned at said interface with a side wall of the first and/or the second connection arm, so that a transition along the multi-arm connection from the side wall of the first connection arm into the end surface of the inside section of the closure element and/or can be flat or stepless from the end surface of the inside section of the closure element into the side wall of the second connection arm. As a result, turbulence in the blood stream and/or clot formation in the extracorporeal blood stream can be avoided or at least minimized by the multi-arm connection when the closure element closes the third connection arm.

In some embodiments, the closure element can penetrate a valve provided on the outside opening of the third connection arm in a fluid-tight or closing manner. The closure element may have a tapered middle section between the inside section and the outside end of the closure element, which is arranged at the level of the valve when the closure element closes the third connection arm. The valve is therefore not constantly stressed and expanded by the closure element when the closure element closes the third connection arm. On the inside section, the closure element can have a cross section that corresponds to the inside cross section of the third connection arm and can seal it.

The closure element and/or the outside opening of the third connection arm can be designed such that a relative arrangement of the closure element with respect to the outside opening of the third connection arm is predetermined, in particular clearly predetermined, for closing the third connection arm. For example, the closure element can only be inserted into the third connection arm in a predetermined relative position, which can in particular correspond to a position in which the end surface of the inside section of the closure element is at the interface between the third connection arm and the first and/or second connection arm with a Side wall of the first and / or the second connection arm is aligned, so that a transition along the multi-arm connection from the side wall of the first connection arm into the end surface of the inside section of the closure element and / or from the end surface of the inside section of the closure element into the side wall of the second connection arm is flat or stepless.

In preferred embodiments of the invention, the first, second and third connection arms of the multi-arm connection can each have a first, a second and a third diameter. The third diameter can be smaller than the first and second diameters. The first diameter and the second diameter may preferably be the same. According to one embodiment, particularly for adult use, the first diameter and the second diameter may be 9.525 mm (3/8") and the third diameter may be 6.35 mm (1/4"), thus in one Can be integrated into the hose system of a common ECMO arrangement. When used on children, the areas can be adjusted or reduced accordingly.

In preferred embodiments, the first, second and third connection arms may define a first, a second and a third direction, respectively. An angle between the first direction and the second direction can preferably be between 135° and 180°. The first and second directions can therefore be aligned with one another (at a relative angle of 180°). An angle between the first direction and the third direction can preferably be between 5° and 45°, particularly preferably between 10° and 30°. An angle between the second direction and the third direction can accordingly preferably be between 135° and 220°. Such angular configurations prove to be particularly advantageous for the purposes of the present invention.

According to a preferred embodiment, the third connection arm can have a fluid connection, preferably a side fluid connection, which can be arranged between both longitudinal ends of the third connection arm, preferably at the outside opening of the third connection arm. The fluid connection can, for example, serve to provide a fluid connection to a flushing line. Through such a flushing line, which can be coupled to the fluid connection of the third connection arm, the interior of the third connection arm can be flushed if necessary, in particular to drain off blood residue, for example using a syringe or a suction mechanism. As a further example, the fluid port may serve to provide fluid connection to a fluid delivery device through which a fluid, such as a liquid preparation or bolus, may be delivered to the third port arm, for example using a syringe or delivery mechanism. The fluid line can be provided with a clamp, for example a so-called “Roberts Clamp”, which is designed to close the fluid line in a controllable manner by compression in order to prevent accidental fluid leakage through the fluid line.

A further aspect of the invention relates to an extracorporeal membrane oxygenation arrangement, i.e. an ECMO arrangement, which comprises a pump device and a measuring system according to the invention, wherein the pump device is fluidly connected to the first connection arm of the multi-arm connection. Such an ECMO arrangement is thus fluidly connected to the first connection arm of the multi-arm connection of the measuring system according to the invention, so that blood can flow through the multi-arm connection into and/or from the ECMO arrangement.

A measuring system according to the invention according to one of the embodiments described above can be used in a method for detecting pressure measurements within a blood vessel of a patient, in particular an artery, in particular during a process for extracorporeal membrane oxygenation, i.e. during ECMO therapy. The same applies to an ECMO arrangement according to the invention. The method can in particular include the following: 1) removing blood from the blood vessel or supplying blood into the blood vessel through the first and second connection arms of the multi-arm connection of the measuring system according to the invention; 2) feeding the measurement catheter of the measurement system into the blood vessel through the third and second connection arms of the multi-arm connection of the measurement system; and 3) recording pressure measurement values at a patient-side end of the measuring catheter of the measuring system according to the invention.

The acquisition of pressure measurements at the patient-side end of the measuring catheter of the measuring system according to the invention can be repeated at different penetration positions of the measuring catheter, in particular at the patient-side end of the measuring catheter. Finally, as described above, a position of the watershed can be determined, especially when ECMO therapy is ongoing.

BRIEF DESCRIPTION OF DRAWINGS

• 1 shows a schematic view of a measuring system according to the invention.
• 2 shows a schematic curve diagram of pressure measurements along a blood vessel, which can be recorded with the measuring system according to the invention.
• 3 shows a schematic view of the patient-side end of the measuring catheter measuring system according to the invention.
• 4 shows a schematic view of the multi-arm connection of the measuring system according to the invention with a closure element.
• 5 is a flow diagram of a method for determining a pressure of a blood stream within a blood vessel of a patient during ongoing ECMO therapy using the measuring system according to the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

In order to promote an understanding of the principles of the invention, reference will now be made to certain preferred embodiments illustrated in the drawings and certain terms will be used to describe the same. It is to be understood, however, that this is not intended to limit the scope of the invention, with consideration being given to such changes and further modifications to the illustrated apparatus and such further applications of the principles of the invention set forth therein as would become apparent to one skilled in the art. to which the invention relates would normally occur now or in the future within the scope defined by the claims.

The 1 shows a schematic view of a measuring system according to the invention that is connected to an ECMO arrangement 40. The measuring system according to the invention comprises a multi-armed connection 10 and a measuring catheter 20. The ECMO arrangement 40 is used to allow or pump extracorporeally oxygenated blood into a blood vessel G of a patient P as part of ECMO therapy. The blood vessel G can in particular show an artery of the patient P, for example a groin artery. The blood flow between the ECMO arrangement 40 and the blood vessel G occurs through the multi-arm connection 10 of the measuring system according to the invention and through a patient-side cannula 30, which provides a connection to the blood vessel G. In other embodiments of the invention, the ECMO assembly 40 may be replaced with another pumping device, which may not necessarily be or include an ECMO assembly.

In this exemplary embodiment, the multi-armed connection 10 is designed as a three-armed Y-shaped connection 10, which has a first connection arm 12, a second connection arm 14 and a third connection arm 16. In the embodiment shown, the first connection arm 12 and the second connection arm 14 are aligned with one another or on one plane, so that an angle α ₁₂ between a direction defined by the first connection arm and a direction defined by the second connection arm is 180°. The third connection arm 16 is arranged obliquely with respect to the first connection arm 12 and the second connection arm 14, with an angle α ₁₃ between the third connection arm 16 and the first connection arm 12 of approximately 20°.

The first connection arm 12, the second connection arm 14 and the third connection arm 16 each have a first diameter D1, a second diameter D2 and a third diameter D3. In the exemplary embodiment the 1 the first connection arm 12 and the second connection arm 14 have the same diameter, which can be, for example, D1 = D2 = 9.525 mm (3/8"), while the third connection arm 16 has a smaller diameter D3 = 6.35 mm (1/4") can be.

The connection arm 12 is connected to the ECMO arrangement 40 by a first connection tube 46 in order to forward a blood flow from the ECMO arrangement 40 into the second connection arm 14. In other embodiments, however, a blood flow from the blood vessel G (first through the second connection arm 14 and then) through the first connection arm 12 can reach the ECMO arrangement 40. The ECMO arrangement 40 is further connected via a second connecting tube 42, via which a blood stream can be drained (venous) or returned (arterial) in order to close a circuit through the ECMO arrangement 40 and the patient's blood vessels. Through connecting tube port 42, the ECMO arrangement 40 can, for example, drain a venous blood flow that is received by another patient-side cannula (not shown) that is connected to a vein (not shown) of the patient P.

The second connection arm 14 is connected to the patient-side cannula 30 in order to pass the blood passed through the first connection arm 12 through the patient-side cannula 30. If that in 1 shown blood vessel G of the patient P is an artery, extracorporeal oxygenated blood provided by the ECMO arrangement 40 is received through the first connection arm 12 into the multi-arm connection 10 and through the second connection arm 14 to the patient-side cannula 30 and to the patient's blood vessel G P forwarded.

The first connection arm 12, the second connection arm 14 and the third connection arm 16 are in fluid communication with one another. The measuring catheter 20, which can have a total length of 100 cm, for example, is inserted through the third connection arm 16 and is guided through the third connection arm 16 and through the second connection arm 14 and penetrates into the patient-side cannula 30 and then into the blood vessel G. The measuring catheter 20 can be inserted into the multi-arm connection 10 through an external opening 17 of the third connection arm 16.

The outside opening 17 of the third connection arm 16 is designed to enable fluid-tight and displaceable guidance of the measuring catheter 20. In this respect, the measuring catheter 20 can be pushed back and forth so that the patient-side end 22 of the measuring catheter reaches correspondingly different positions or penetration depths within the blood vessel G without blood or other liquids escaping through the outside opening 17 of the third connecting arm 16 comes. For this purpose, a check valve (not shown) can be arranged on the outside opening 17 of the third connection arm 16.

The measuring catheter 20 is also set up to measure pressure measurements at the patient-side end 22. For each penetration position of the patient-side end 22 of the measuring catheter 20 along the blood vessel G, which can be varied with a corresponding displacement of the measuring catheter 20, the measuring catheter 20 can record an associated pressure measurement value, which corresponds to a fluid or blood pressure at the respective point within the blood vessel G corresponds.

The penetration positions of the measuring catheter 20, in particular its end on the patient side, and/or the pressure measurements measured by the measuring catheter 20 can be recorded by a processor unit 50, which can be communicatively connected to the measuring catheter 20. In the in the 1 In the embodiment shown, the processor unit 50 is connected to an end of the measuring catheter 20 remote from the patient.

Alternatively or additionally, the measuring catheter 20 can be provided with length markings 21, which enable a visual determination of the penetration position of the measuring catheter 20 by an operator or user of the measuring catheter 20. The length markings 21 can, for example, be evenly distributed along the measuring catheter 20 at regular intervals of 5 cm or 10 cm.

In the in the 1 In the embodiment shown, a section of the measuring catheter 20, which extends between an end of the measuring catheter 20 remote from the patient and the outside opening 17 of the third connection arm 16, is covered by a protective cover 26. The protective cover 26, which can be designed, for example, as a hose-shaped or accordion-shaped plastic cover, is attached to the third connection arm 16, in particular to the outside opening 17, at its connection-side end 27. For this purpose, a corresponding fastening mechanism, for example a bayonet mechanism, can be provided.

The protective cover 26 enables a contact-free displacement of the measuring catheter 20 by a user or operator of the measuring system according to the invention. If the user or operator wants to move the measurement catheter 20, he or she can exert a displacement force on the measurement catheter 20 through the protective cover 26 without directly touching the measurement catheter.

If the measuring catheter 20 is provided with length markings 21, the protective cover 26 and/or the multi-arm connection 10 can be at least partially transparent so that the length markings are visible from outside the protective cover or the multi-arm connection 10. However, this is not necessarily the case, since the length markings 21 can also be detected by non-optical detection, for example by electronic or magnetic detection.

The third connection arm 16 has an optional fluid connection 32 which provides a fluid connection with a fluid line 31 which is coupled or can be coupled to the fluid connection 32 of the third connection arm 16. The fluid line 31 can, for example, function as a flushing line through which the interior of the third connection arm 16 can be flushed if necessary, in particular to remove blood residue from the multi-arm connection 10, for example using a syringe or a suction mechanism (not shown). The fluid port 32 and the fluid line 31 may also serve to deliver a fluid, such as a liquid preparation or bolus, to the third port arm, for example using a syringe or a delivery mechanism. The fluid line 31 may be provided with a clamp 33 to occlude the fluid line 31.

To record the pressure measurement values at the patient-side end 22, the measuring catheter 20 can include a pressure sensor 24, which can be arranged directly at the patient-side end 22 in order to directly measure the pressure measurement values there. The pressure measurements measured by the pressure sensor 24 can be transmitted to the processor unit 50 through a wire connection guided through the measuring catheter 20. Alternatively or additionally, the measuring system according to the invention can comprise a pressure sensor 25, which is hydrostatically connected to the patient-side end 22 of the measuring catheter 20. In the in the 1 In the exemplary embodiment shown, the pressure sensor 25 is integrated into the processor unit 50 or connected thereto. The pressure sensor 25 can detect the pressure measurement value there via the liquid column up to the patient-side end 22 of the measuring catheter 20 (eg analogous to a conventional arterial pressure measurement value). A fluid connection between the measuring catheter 20 and the pressure sensor 25 can take place, for example, via a conventional Luer lock connection (not shown).

In the in the 1 In the exemplary embodiment shown, the protective cover 26 is attached to the processor unit 50 at the end of the measuring catheter 20 remote from the patient. A non-sterile, patient-remote end section of the measuring catheter 20 is connected to the processor unit 50.

The processor unit 50 can be set up to record the penetration positions of the patient-side end 22 of the measuring catheter 20 along the blood vessel G and the respective pressure measurements. The processor unit 50 can be set up to automatically detect the penetration positions, for example using appropriate sensors. The processor unit can, for example, be connected to a detection device that is set up to detect the length markings 21. Alternatively or additionally, a user or operator of the measuring system according to the invention can determine the penetration positions based on the length markings 21 and possibly enter them into the processor unit 50, for example by means of a suitable user interface. As stated above The processor unit 50 can receive the information about the pressure measurements at the patient-side end 22 of the measuring catheter 20 from the pressure sensor 24 and/or from the pressure sensor 25.

The 2 shows a schematic curve of the pressure measurement values for different penetration positions or penetration depths of the patient-side end 22 of the measuring catheter 20 along the blood vessel G of the patient P, which can be recorded using the measuring system according to the invention, for example by the processor unit 50. In a first penetration depth range A, which immediately adjoins the patient-side cannula 30, the pressure measurement values initially gradually decrease as the penetration depth of the measuring catheter 20 increases, the deeper the patient-side end 22 of the measuring catheter 20 penetrates into the blood vessel G. This is due to the increasing back pressure of the blood pumped from the heart towards the patient-side cannula, which increases with increasing proximity to the heart and increasingly neutralizes the own pressure of the blood pressure driven by the ECMO arrangement 40. In a second (middle) penetration depth range B, a low point T is reached in which the measured pressure value is minimal. From this point onwards, the measured pressure values in a third penetration depth range C increase again with further introduction of the measuring catheter 20, since after the impact point of both blood streams has been exceeded further towards the heart, the pressure of the blood stream pumped by the heart increases again. The plateau level can be higher in the first penetration depth range A than in the second penetration depth range B, depending on the pumping power of the heart and/or on the settings of the ECMO arrangement 40.

By determining the position of the low point T in the middle penetration depth range B, in particular based on the corresponding value of the penetration depth, the exact position of the point of impact of both blood streams or the watershed can be determined.

The 3 Thematic detailed view of the patient-side end 22 of the measuring catheter 20. As shown here, the measuring catheter 20 has a lumen L, through which a fluid connection between the patient-side end 22 of the measuring catheter 20 and the end of the measuring catheter remote from the patient, in particular the processor unit 50 and / or the pressure sensor 25, can be produced. A hydrostatic connection between the patient-side end 22 and the pressure sensor 25 can take place through the lumen L. Alternatively or additionally, the lumen L can be used, for example, to take blood samples and/or to add a fluid, such as an infusion, into the blood vessel G.

The detailed view of the 3 also shows the pressure sensor 24, which is arranged at the patient-side end 22 of the measuring catheter 20. The 3 also shows that the patient-side end 22 of the measuring catheter 20 or its front tip is blunt in order to avoid injuries to the inner walls of the blood vessel G by the tip of the measuring catheter 20.

The inner lumen L of the measuring catheter opens at the patient-side end into a patient-side opening O, which is longitudinally aligned. With respect to a cross section of the measuring catheter 20 in a plane perpendicular to the longitudinal direction of the measuring catheter 20, the patient-side opening O is arranged centrally.

Like in the 4 shown, the measuring system according to the invention can further comprise a closure element 28, which is set up for a precise and/or fluid-tight closure of the outside opening 17 of the third connection arm 16. The 4 shows a detailed view of a state of the multi-arm connection 10 of the measuring system according to the invention when the closure element 28 closes the third connection arm 16 and also shows a separate view of the closure element 28 when it does not close the third connection arm 16.

Like in the 4 shown, the closure element 28 has an inside section 29, which plugs the third connection arm 16 in a form-fitting manner when the closure element 28 closes the third connection arm 16. Like in the 4 shown in detail, the closure element 28 or its inside section 29i extends to the interface of the third connection arm 16 with the first and second connection arms 12, 14. An end surface 29e of the inside section 29i is oriented in such a way that it is in contact with the side walls 12W and 1.4w of the first connection arm 12 or the second connection arm 14 lies flush when the closure element 28 closes the third connection arm 16.

The closure element 28 can penetrate a valve 23 provided on the outside opening 17 of the third connection arm 16 in a fluid-tight or closing manner. Like in the 4 shown, the closure element 28 can have a tapered or narrower central section 29m between the inside section 29i and an outside section 29a adjoining the outside end of the closure element 28. When the closure element 28 closes the third connection arm 16, the tapered middle section 290m is arranged at the height of the valve 23, so that the valve 23 is not constantly stressed and expanded by the closure element 28. The one in the third The fluid connection 32 formed by the th connection arm 16 is preferably formed close to the outside opening 17 and can be sealed in a sealing manner by the outside section 29a of the closure element 28 when the closure element 28 closes the third connection arm 16.

A mechanism M can be provided on the closure element 28 and/or on the third connection arm 16, for example a bayonet mechanism, in order to releasably lock the closure element 28 on the third connection arm 16 when the closure element 28 closes the third connection arm 16. This can be the same mechanism with which the protective cover 26 can be attached to the outside opening 17 of the third connection arm 16 if the closure element 28 does not close the third connection arm 16. The mechanism M can uniquely determine a relative arrangement of the closure element 28 with respect to the external opening 17 of the third connection arm 16, so that it is only possible to arrange the closure element 28 in a predetermined position in order to close the third connection arm 16 with the closure element 28 close.

• Bei Schritt 102 wird Blut durch den ersten Anschlussarm 12 und den zweiten Anschlussarm 14 des mehrarmigen Anschlusses 10 des erfindungsgemäßen Messsystems vom Blutgefäß G des Patienten P abgeführt oder in das Blutgefäß G zugeführt. Dies erfolgt im Rahmen einer ECMO-Therapie.
• Bei Schritt 104 wird der Messkatheter 20 des erfindungsgemäßen Messsystems durch den dritten Anschlussarm 16 und den zweiten Anschlussarm 14 des mehrarmigen Anschlusses 10 des erfindungsgemäßen Messsystems, sowie durch die patientenseitige Kanüle 30, in das Blutgefäß G eingeführt.
• Bei Schritt 106 werden eine oder mehrere Druckmesswerte an dem patientenseitigen Ende 22 des Messkatheters 20 des Messsystems erfasst, wenn sich das patientenseitige Ende 22 des Messkatheters 20 innerhalb des Blutgefäßes G des Patienten P befindet. Der Schritt 106 kann bei verschiedenen Eindringpositionen des Messkatheters 20, insbesondere des patientenseitigen Ende 22 des Messkatheters 20, wiederholt werden, um entsprechende Druckmesswerte zu erfassen. Anhand der erfassten Druckmesswerte für die verschiedene Eindringpositionen kann die Position der Wasserscheide bestimmt werden.

The 5 shows a flow diagram of a method 100 for recording pressure measurements within a blood vessel of a patient while ECMO therapy is ongoing using the measuring system according to the invention, for example the measuring system of 1-4 . The procedure includes the following steps:

• In step 102, blood is removed from the blood vessel G of the patient P or fed into the blood vessel G through the first connection arm 12 and the second connection arm 14 of the multi-arm connection 10 of the measuring system according to the invention. This is done as part of ECMO therapy.
• In step 104, the measuring catheter 20 of the measuring system according to the invention is introduced into the blood vessel G through the third connection arm 16 and the second connection arm 14 of the multi-arm connection 10 of the measuring system according to the invention, as well as through the patient-side cannula 30.
• In step 106, one or more pressure measurements are recorded at the patient-side end 22 of the measuring catheter 20 of the measuring system when the patient-side end 22 of the measuring catheter 20 is located within the blood vessel G of the patient P. Step 106 can be repeated at different penetration positions of the measuring catheter 20, in particular the patient-side end 22 of the measuring catheter 20, in order to record corresponding pressure measurement values. The position of the watershed can be determined based on the pressure measurements recorded for the various penetration positions.

Although preferred exemplary embodiments are shown and described in detail in the drawings and the foregoing description, these should be viewed as purely exemplary and not as a limitation of the invention. In this connection, it should be noted that only the preferred exemplary embodiments are shown and specified, and that protection should be given to all variations and modifications that now or hereafter come within the scope of the invention as defined in the claims.

Claims (13)

Measuring system for acquiring pressure measurements in a patient's blood vessel, comprising: a multi-arm connection (10), which comprises a first connection arm (12), a second connection arm (14) and a third connection arm (16), which are in fluid communication with one another, wherein the first connection arm (12) is adapted to be fluidly connected to a pump device (40) in order to pass a fluid through; wherein the second connection arm (14) is designed to be connected to a patient-side cannula (30) in order to pass the fluid passed through the first connection arm (12) through the patient-side cannula (30); and a measuring catheter (20), which can be inserted into the patient-side cannula through the third connecting arm (16), the third connecting arm (16) being designed to accommodate the measuring catheter (20) in a fluid-tight and displaceable manner and through the second connecting arm (14). to supply the patient-side cannula (30), and wherein the measuring catheter (20) is set up to measure pressure measurements at a patient-side end (22) of the measuring catheter (20). measuring system Claim 1 , which further comprises a processor unit (50) which is communicatively connected to the measuring catheter (20) and is set up to detect an penetration position of the measuring catheter (20), in particular the patient-side end (22) of the measuring catheter (20). measuring system Claim 2 , wherein the processor unit (50) is further set up to record pressure measurements measured by the measuring catheter (20) and associated penetration positions of the measuring catheter (20). Measuring system according to one of the preceding claims, wherein the measuring catheter (20) lengths markings (21) for determining a penetration position of the measuring catheter (20), in particular the patient-side end (22) of the measuring catheter (20). Measuring system according to one of the preceding claims, wherein the measuring catheter (20) comprises a pressure sensor (24), which is preferably arranged at the patient-side end (22) of the measuring catheter (20) and is set up to measure the pressure measurements at the patient-side end (22) of the measuring catheter (20) to measure; and/or wherein the measuring system further comprises a pressure sensor (25) which is hydrostatically connected to the patient-side end (22) of the measuring catheter (20) and is set up to measure the pressure measurements at the patient-side end (22) of the measuring catheter (20). . Measuring system according to one of the preceding claims, wherein the patient-side end (22) of the measuring catheter (20) is blunt. Measuring system according to one of the preceding claims, wherein the measuring catheter (20) is accommodated in a protective cover (26) which encloses a section of the measuring catheter (20) outside the multi-armed connection (10) and is designed to be at a connection-side end (27). to be attached to the third connection arm (16), the protective cover being designed to guide a contact-free displacement of the measuring catheter (20). Measuring system according to one of the preceding claims, further comprising a closure element (28) for closing the third connection arm (16), in particular an external opening (17) of the third connection arm (16), wherein the closure element (28) preferably closes the third connection arm (16). closes precisely and/or fluid-tight; wherein the closure element (28) preferably has an inside section (29i) for plugging the third connection arm (16), the inside section (29i) preferably having an end surface (29e) which is designed to be connected to a side wall (12w, 14w ) of the first and / or the second connection arm (14) to lie flush when the closure element (28) closes the third connection arm (16). Measuring system according to one of the preceding claims, wherein an external opening (27) of the third connection arm (16) is provided with a valve for blood-tight closure of the third connection arm (16). Measuring system according to one of the preceding claims, wherein the first, second and third connection arms (16) each have a first, second and third diameter, the third diameter (D3) being smaller than the first and second diameters (D1, D2); and/or wherein the first diameter (D1) and the second diameter (D2) are the same. Measuring system according to one of the preceding claims, wherein the first connection arm (12) defines a first direction, wherein the second connection arm (14) defines a second direction, and wherein the third connection arm (16) defines a third direction, wherein an angle (α ₁₂ ) between the first direction and the second direction is preferably between 135° and 180° and/or an angle (α ₁₃ ) between the first direction and the third direction is preferably between 5° and 45°, particularly preferably between 10° and 30° . Measuring system according to one of the preceding claims, wherein the third connection arm (16) has a preferably lateral fluid connection (32). Extracorporeal membrane oxygenation arrangement comprising a pumping device (40) and a measuring system according to one of the preceding claims, wherein the pumping device (40) is fluidly connected to the first connection arm (12) of the multi-arm connection (10).

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